European Journal of Mechanics A-Solids最新文献

{"title":"Transient wave propagation in a 1-D gradient model with material nonlinearity","authors":"Andrei B. Fărăgău ,&nbsp;Marten Hollm ,&nbsp;Leo Dostal ,&nbsp;Andrei V. Metrikine ,&nbsp;Karel N. van Dalen","doi":"10.1016/j.euromechsol.2024.105543","DOIUrl":"10.1016/j.euromechsol.2024.105543","url":null,"abstract":"<div><div>A novel nonlinear 1-D gradient model has been previously proposed by the authors, combining (i) the higher-order gradient terms that capture the influence of material micro-structure and (ii) a nonlinear softening material behavior through the use of a hyperbolic constitutive model. While the previous study focused on the existence and properties of solitary-type waves, the current study focuses on the characteristics of the transient wave propagation in the proposed model. Findings show that as nonlinearity increases, the bulk of the wave slows down, and its shape becomes more distorted in comparison to the response of the linear system. The energy analysis reveals that, unlike the linear system, the nonlinear one continuously exchanges energy, in which the kinetic energy decreases over time while the potential one increases. Furthermore, the spectral (wavenumber) energy density of the nonlinear-<em>elastic</em> system presents peaks at large wavenumbers. However, these are eliminated when a small amount of linear viscous damping is added indicating that they are not physically relevant. A notable feature that persists despite the presence of damping is the formation of small-amplitude waves traveling in the opposite direction to the main wave. Generalized continua, like gradient elasticity models, miss the small energy scatter by the micro-structure. This study shows that adding material nonlinearity to a homogeneous generalized continuum can capture reverse energy propagation, though at much smaller magnitudes than the main wave. These findings shed light on the characteristics of the transient wave propagation predicted by the proposed nonlinear 1-D gradient model and its applicability in, for example, predicting the seismic site response.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105543"},"PeriodicalIF":4.4,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A generalized physics-driven neural network for micromechanical and microstructural evolution of heterogeneous materials","authors":"Zhihao Xiong,&nbsp;Pengyang Zhao","doi":"10.1016/j.euromechsol.2024.105551","DOIUrl":"10.1016/j.euromechsol.2024.105551","url":null,"abstract":"<div><div>Physics-driven neural networks (PDNNs) have shown great promise for micromechanical applications, but are currently facing challenges in terms of generalization for tackling time-dependent problems of inhomogeneous materials. Here we present a generalized PDNN (GPDNN) framework for micromechanical and microstructural evolution by incorporating the Fourier feature layer, multi-output scheme, and self-adaptive learning weighting. This GPDNN retains the advantages of PDNN, i.e., utilizing unlabeled data and avoiding unphysical behavior, and formulates both strong form and weak form based loss functions. The generality and accuracy of GPDNN are then demonstrated across various time-dependent problems, including Eshelby's inclusion problem, elastodynamics of porous and polycrystalline materials, and microstructure evolution governed by phase-field equations. The effect of multi-output scheme and self-adaptive learning weighting, the key enablers of performance improvement for GPDNN, are further analyzed, together with computational efficiency comparison between GPDNN and other methods. It is shown that GPDNN achieves higher efficiency and accuracy as compared to PDNN in solving multiscale dynamical problems, highlighting the proposed GPDNN framework as a more generalized tool for addressing critical challenges in computational micromechanics and materials science.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105551"},"PeriodicalIF":4.4,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing sound transmission loss of a piezoelectric metastructure shell in the low-frequency range using negative-capacitance shunting","authors":"Yisheng Zheng ,&nbsp;Huaibing Yuan ,&nbsp;Wujun Feng ,&nbsp;Yegao Qu ,&nbsp;Yajun Luo","doi":"10.1016/j.euromechsol.2024.105554","DOIUrl":"10.1016/j.euromechsol.2024.105554","url":null,"abstract":"<div><div>To address the low-frequency sound insulation problem of shell structures, we explore and exploit a piezoelectric metastructure shell (meta-shell) with negative-capacitance (NC) shunting. The effective elastic parameters of the meta-shell are derived with considering the impacts of NC shunting, thereby enabling achieving its effective acoustic impedance for computing the sound transmission loss (STL). By configurating the piezoelectric shunting as such that the effective tensional rigidity of the meta-shell is increased, its ring frequency would be improved and therefore the low-frequency sound insulation performance below which is generally enhanced. Both the effective impedance method and the finite-element (FE) method are employed to analyze STL of the meta-shell. The sound transmission behaviors are further interpreted through dispersion relations of unit cells. It is found that, due to the increasing of rigidity, the two dispersion branches of the bending-tensional modes are overall shifted to higher frequency regimes through NC piezoelectric shunting. On the other hand, they are also separated far away in the frequency domain. It leads to quite distinct characteristic frequencies for sound waves with different incidence angles. Therefore, under the vertical incidence of sound waves, the low-frequency soundproof performance is enhanced much more significantly than that under the conditions with relatively large incidence angles. The scenarios with different values of negative capacitance, covering ratios and thickness ratios of piezoelectric patches are considered for comprehensively evaluating their impacts on the low-frequency soundproof performance of the meta-shell. Distinguished with metastructures relying on the local-resonance mechanism, the proposed scheme could improve sound insulation performance of shell structures in the broadband low-frequency range.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105554"},"PeriodicalIF":4.4,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wave propagation in nonviscously damped phononic materials via precise integration method and deep learning","authors":"Taufeeq Ur Rehman Abbasi ,&nbsp;Faizan Faraz ,&nbsp;Muhammad Anser Bashir ,&nbsp;Weiqiu Chen ,&nbsp;Bin Wu","doi":"10.1016/j.euromechsol.2024.105542","DOIUrl":"10.1016/j.euromechsol.2024.105542","url":null,"abstract":"<div><div>The sensitivity of time-step size in direct integration methods presents significant challenges in achieving high computational accuracy, performing precise hysteresis analysis, and integrating deep neural networks into the study of wave propagation in nonviscously damped phononic materials. Addressing these challenges necessitates a reliable method capable of accurately analyzing wave propagation in such materials. Motivated by these needs, this paper introduces a precise direct integration method (PDIM) for transient wave propagation analysis in phononic materials. The proposed method incorporates an anelastic displacement field (ADF) model to account for complex, frequency-dependent damping behaviors while maintaining minimal model-order requirements. Two asymmetric state-space formulations based on Bloch–Floquet theory are derived to construct eigenvalue problems. To efficiently determine the dissipation behavior of propagating waves in phononic materials, a PDIM based on an asymmetric state-space formulation is developed. Wave propagation behavior in phononic materials is investigated using numerical examples, including a diatomic lattice structure, a multi-frequency vibration absorber, and a nonviscously damped rod. Using experimental datasets, the force–displacement hysteresis behavior of the ADF model is analyzed to accurately characterize the energy dissipation of the multi-frequency vibration absorber. The performance of the PDIM is compared to that of the existing accurate methods and the finite element time domain (FETD) method from the literature, with evaluations based on implementation, accuracy, stability, and precision. The PDIM provides precise results that approach accurate solutions across different time steps. By eliminating the need for acceleration calculations at each time step, the PDIM demonstrates a significant advantage over the FETD method. To solve wave propagation problems in a diatomic lattice structure, a comparative study between the PDIM and physics-informed neural networks (PINNs) is conducted. With carefully designed network architecture, PINNs show promising results that closely match the predictions obtained from the PDIM. Additionally, the nonviscous damping effect on the wave propagation characteristics of phononic materials is analyzed, revealing that viscoelasticity contributes to the widening of the bandgaps in nonviscously damped phononic materials.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105542"},"PeriodicalIF":4.4,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A mechanics model of coating-assisted strategy for shape fixation of 3D mesostructures based on buckling-guided assembly","authors":"Shiwei Xu ,&nbsp;Zhenjia Tang ,&nbsp;Ruoxi Yang ,&nbsp;Zhaoguo Xue ,&nbsp;Yonggang Huang ,&nbsp;Yihui Zhang","doi":"10.1016/j.euromechsol.2024.105549","DOIUrl":"10.1016/j.euromechsol.2024.105549","url":null,"abstract":"<div><div>Buckling-guided three-dimensional (3D) assembly is an attractive manufacturing method that provides a versatile route to complex 3D mesostructures in a wide range of high-performance materials, which has enabled developments of 3D devices with unique functionalities and/or enhanced performances. While an elastomer substrate is required to serve as the platform of 3D assembly, the existence of such a substrate could impede practical uses of assembled 3D mesostructures in certain applications scenarios. As such, several strategies have been proposed to enable the shape fixation of 3D mesostructures after separation from the assembled substrate. Among them, the coating-assisted strategy does not impose additional constraints on structural designs (e.g., incorporating specific mechanical interlocks) or applicable material types (e.g., metals or shape memory polymers/alloys). Moreover, the shape fixation effects of coating-assisted strategy can be effectively controlled by optimizing key design parameters. Although the development of a rational design method that can guide the selection of design parameters related to the coating-assisted strategy is of great importance, it has not been explored. This paper develops a mechanics model of the shape fixation in a bridge-shaped ribbon structure formed through buckling of a straight ribbon structure and coating of an additional fixation layer. An analytical solution of the springback ratio in terms of the modulus ratio and the thickness ratio between structure/fixation layers as well as the prestrain used in the 3D assembly, is obtained, showing good agreements with finite element analyses (FEA) and experimental results. By introducing a modification factor, this solution can be extended to complexly shaped 3D mesostructures, such as cross-ribbon, helical-shaped and crane-like mesostructures. Guided by the developed model, highly complex freestanding 3D mesostructures such as ribbon-shaped mesostructures, and origami/kirigami-inspired mesostructures are demonstrated.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105549"},"PeriodicalIF":4.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation and performance analysis of a novel double-layer sandwich composite structure","authors":"Caixia Jia ,&nbsp;Zhuo Zhang ,&nbsp;Qian Wang ,&nbsp;Yunpeng Qiu ,&nbsp;Zhixin Li ,&nbsp;Bowen Feng","doi":"10.1016/j.euromechsol.2024.105545","DOIUrl":"10.1016/j.euromechsol.2024.105545","url":null,"abstract":"<div><div>In this paper, a novel double-layer sandwich composite structure was designed based on the synergistic integration of a trapezoidal corrugation (TC) core and a double arrow (DA) core. A combination of experiment and simulation was employed to analyze the flexural performance of the new sandwich structure and reveal its unique failure mechanism. As the double-layer sandwich composite structure containing trapezoidal corrugation &amp; double arrow (C&amp;A) core was able to avoid large bending deformation through the stiffness advantage of the lower DA core and reduce the debonding damage between the core and the panel, the upper TC core was capable of absorbing energy stably through core collapse under bending loads. Results showed that the load-displacement curve of the double-layer sandwich structure with C&amp;A cores experienced two load peaks with increasing displacement, and the later peak was higher than the first peak, and when compared with the two single-layer sandwich structures with TC core and DA core, the load efficiency of the double-layer sandwich structure was improved by 164.53% and 185.49%, while the specific energy absorption was improved by 87.43% and 71.40%, respectively.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105545"},"PeriodicalIF":4.4,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symmetric normalization algorithm for estimating physiological strain in bones","authors":"Petr Henyš ,&nbsp;Enrico Dall’Ara ,&nbsp;Saulo Martelli","doi":"10.1016/j.euromechsol.2024.105539","DOIUrl":"10.1016/j.euromechsol.2024.105539","url":null,"abstract":"<div><div>This study evaluates the accuracy of the Symmetric Normalization (SyN) algorithm in estimating physiological bone deformations using digital volume correlation (DVC), comparing it to the well-established BoneDVC algorithm commonly employed in bone biomechanics. Using high-resolution micro-CT images of the proximal femur and synthetic deformation models, we assessed the precision and robustness of each algorithm. Findings indicate that SyN produces comparable error levels to BoneDVC, with reduced sensitivity to noise and sampling rates. In contrast, BoneDVC’s accuracy is more dependent on nodal spacing configuration, which impacts deformation estimates. These results suggest that SyN, with its efficient noise handling and computational advantages, may serve as a viable alternative for bone deformation analysis in DVC experiments. This study contributes novel insights into the application of SyN-based algorithms in biomechanical research, offering a foundation for future investigations across diverse bone structures and experimental settings.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105539"},"PeriodicalIF":4.4,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the different grain-size dependences of flow stress and spall strength of nanocrystalline Cu under shock loading","authors":"Xia Tian ,&nbsp;Linglong Sun ,&nbsp;Wanghui Li ,&nbsp;Meizhen Xiang ,&nbsp;Junzhi Cui ,&nbsp;Yi Liao","doi":"10.1016/j.euromechsol.2024.105546","DOIUrl":"10.1016/j.euromechsol.2024.105546","url":null,"abstract":"<div><div>Understanding the material response and material strength under dynamic loading is crucial for optimized design of advanced material serving in extreme conditions. Flow stress and spall strength are typical measured material strengths in shock loading. However, the correlation of the two strengths is not well understood. Here we use large-scale molecular dynamics simulations to demonstrate that flow stress and spall strength of nanocrystalline Cu have obviously different variation tendencies upon grain refinement at nanoscale. The flow stress reveals a transition from Hall-Petch (HP) to inverse Hall-Petch (IHP) behaviors as grain size decreases. The HP - IHP transition of flow stress is mainly attributed to the competition of grain boundaries strengthening effect by blocking and absorbing dislocations and the grain boundaries weakening effects including GB sliding and grain rotations. However, the grain size dependence of spall strength mainly shows an inverse Hall-Petch relationship, i.e., spall strength generally decreases as grain size decreases. This is mainly due to the role of grain boundaries as preferred void nucleation sites. For finer grain size, the larger volume fraction of grain boundaries and junctions facilitates damage nucleation and results in larger amount of voids and lower tensile strength.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105546"},"PeriodicalIF":4.4,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Buckling of micromorphic Timoshenko columns","authors":"N. Challamel ,&nbsp;S. El-Borgi ,&nbsp;M. Trabelssi ,&nbsp;J.N. Reddy","doi":"10.1016/j.euromechsol.2024.105537","DOIUrl":"10.1016/j.euromechsol.2024.105537","url":null,"abstract":"<div><div>This paper presents exact solutions for the buckling of a micromorphic Timoshenko column under general boundary conditions. The shear effect is introduced through Engesser’s shear column theory.This problem can also be formulated as a nonlocal strain gradient Timoshenko column that uses nonlocal kernels for both the strain (curvature and shear strain for the Timoshenko beam) and its derivative. It is shown that both models yield the same governing equations but differ in potential energy definiteness. The micromorphic model predicts hardening effects, while the nonlocal strain gradient model captures both softening and hardening. The buckling problem is formulated as an eighth-order differential eigenvalue problem, associated with eight variationally-consistent boundary conditions. Analytical buckling solutions are obtained for various boundary conditions using Cardano’s method. Closed-form solutions of the buckling load may also be obtained for some specific boundary conditions, including the higher-order nonlocal boundary conditions. The role of variationally-consistent higher-order boundary conditions is specifically addressed. The softening or stiffening contributions of the small length-scale terms are discussed for all the considered boundary conditions, including simply-supported, clamped-free, clamped–clamped, and clamped-simply-supported cases. The role of shear contribution is also analyzed for this micromorphic Engesser–Timoshenko column.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105537"},"PeriodicalIF":4.4,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The propagation of axisymmetric guided waves in cylindrical rods based on fractional order thermo-visco-elastic model","authors":"Lina Zhao,&nbsp;Peijun Wei","doi":"10.1016/j.euromechsol.2024.105541","DOIUrl":"10.1016/j.euromechsol.2024.105541","url":null,"abstract":"<div><div>The dispersion and attenuation of axisymmetric guided waves in cylindrical rod are studied with microstructure effects on the mechanical and thermal behavior considered simultaneously. The non-local strain gradient elasticity is used to model the microstructure effects on the mechanical behavior. The fractional order derivative is used to model the history-dependent viscoelasticity and thermal conduction. The nonlocal effects, the strain gradient effects, the non-Fourier heat conduction effects and the thermoelastic coupled effects on the axisymmetric torsional and longitudinal waves are explored based on the analytical formulation and the numerical examples. The investigation reveals that size effects have nonnegligible effects on the propagation of guided waves. The nonlocal and strain gradient effects influence mainly the dispersion while the non-Fourier heat conduction and viscoelasticity influence mainly on the attenuation feature.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"111 ","pages":"Article 105541"},"PeriodicalIF":4.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}